CD3+CD8+CD161high Tc17 cells are depleted in HIV‐Infection and related to the level of immune reconstitution

Purpose The existence of CD8+cells with pro‐inflammatory properties referred to as Tc17 cells has recently been acknowledged. While it is evident that CD4+pro‐inflammatory IL‐17‐producing Th17 cells are important in the regulation of chronic viral infections, the role of Tc17 cells is largely unknown. Tc17 cells are characterized by expression of high levels of CD161 (CD161high). We hypothesized that Tc17 cells are involved in immune regulation in HIV‐ infection. Methods 67 HIV‐infected patients were included in a cross‐sectional study. All patients had nadir CD4 counts<200 cells/µL, fully suppressed viral loads, and had been on cART for at least 2 years. Three groups were defined: Immunological Non Responders (INR, CD4 counts<200 cells/µL), Intermediate Responders (IR, CD4 counts 200–500 cells/µL), and Responders (RES, CD4 counts>500 cells/µL). Percentages of CD8+cells expressing CD3+CD8+CD161high were evaluated using flow cytometry. Additionally, Production of IL‐17 in phytohaemagglutinin(PHA)‐stimulated peripheral blood was determined by Luminex. For statistics Kruskall Wallis test followed by Mann‐Whitney U test was used. Data are given as medians. Summary of results INR had lower levels of Tc17 cells compared to IR, RES and controls (0.4%, 1.0%, 2.1%, 6.1%, p values<0.05). All HIV‐infected patients had lower levels than controls (p values<0.0001). Furthermore, all HIV‐infected patients displayed lower production of IL‐17 in peripheral blood compared to controls (p values<0.001).